[ plan-i-tair-ee-uh m ]
/ ˌplæn ɪˈtɛər i əm /

noun, plural plan·e·tar·i·ums, plan·e·tar·i·a [plan-i-tair-ee-uh] /ˌplæn ɪˈtɛər i ə/.

an apparatus or model representing the planetary system.
a device that produces a representation of the heavens by the use of a number of moving projectors.
the building or room in which such a device is housed.

Origin of planetarium

1765–75; < New Latin, noun use of neuter of Latin planētārius planetary; cf. -arium Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for planetarium

British Dictionary definitions for planetarium


/ (ˌplænɪˈtɛərɪəm) /

noun plural -iums or -ia (-ɪə)

an instrument for simulating the apparent motions of the sun, moon, and planets against a background of stars by projecting images of these bodies onto the inside of a domed ceiling
a building in which such an instrument is housed
a model of the solar system, sometimes mechanized to show the relative motions of the planets
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012